1. Field of the Invention
The present invention relates to a network monitor system, and a data amount counting method and a program for use in the system, and, in particular, to a method of monitoring data flowing on a network.
2. Description of the Related Art
As a conventional method of monitoring data flowing on a network, a method has heretofore been adopted which at first sets a path such that the data passes through a network monitor apparatus and accumulates an amount of passed data by a network monitor apparatus. In this case, the network monitor apparatus calculates and generates accounting information in response to the data amount.
However, in this method, the data has to be sure to pass through the network monitor apparatus. Otherwise, the accounting information cannot be generated and, as a result, no accounting information can be generated with respect to the data which does not pass through the network monitor apparatus. In addition, the generation of the accounting information is limited by a processing capability of the network monitor apparatus.
To solve the problem, a technique described in Japanese Patent Application Laid-Open Hei 11-191766, namely, 1999-191766 comprises: counting an amount of communication data based on a source Internet protocol (IP) address during data reception; and counting the amount of communication data based on a destination IP address during data transmission.
Specifically, the above-described conventional method of monitoring the data flowing on the network monitors the communication data amount based on the source and destination IP addresses during the data transmission/reception. Therefore, it is impossible to monitor the communication data amount in consideration of a group or a sub-divided group defined by any other conditions than the IP address.